The Conair Medium Room Air Purifier has been an improvement to my life. It's been the worst allergy year in a long time, and I decided to put the air purifier in the bedroom. The unit is lightweight and you just plug it in and use it, with no fuss. There was a noticeable difference after one night with it: my breathing had improved and my eyes were not irritated, as they have been upon awakening. After a few nights, I was feeling more well rested in the morning. 
One issue worthy of mention is the sound. While it isn't "noisy," per se, it's not whisper quiet, either; it does make a low whoosh. If you require total silence in order to sleep, this is not the item for you; however, I enjoy a bit of white noise while falling asleep, so I consider it an added benefit. 
I received this item for free in exchange for my honest opinion.